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About Michael J. Miller

Miller, who was editor-in-chief of PC Magazine from 1991 to 2005, authors this blog for PC Magazine to share his thoughts on PC-related products. No investment advice is offered in this blog. All duties are disclaimed. Miller works separately for a private investment firm which may at any time invest in companies whose products are discussed in this blog, and no disclosure of securities transactions will be made.

Lately, most of the attention in the chips market has been on the latest generation
of desktop and notebook chips that combine CPU and graphics functions
together in a single chip, such as Intel's "Sandy Bridge" family and
AMD's Fusion chips. This has changed the landscape for mainstream
desktop and notebook computers, and I expect graphics will be a main
point of differentiation among those kinds of chips in the years to
come.

However, server chips and the highest-end desktop chips are different; server chips typically don't need much in the way of graphics, while
high-end clients usually require separately discrete graphics boards. So
this fall, I expect we'll be hearing a lot more about chips without
integrated graphics--notably, chips based on AMD's new Bulldozer core and
Intel's SandyBridge architecture, both based on 32nm process
technology.
AMD has talked a lot more about Bulldozer, which represents the bigger change in architecture--arguably AMD's biggest microarchitecture change in the past half dozen years. Bulldozer is based on a set of modules, each of which contains two integer cores and a single floating point core, along with a shared instruction cache and fetch and decode logic.

AMD is now widely expected to ship the first Bulldozer implementations next month. (As of last fall, the desktop version was supposed to be in the second quarter, with the server version in the third quarter, but it seems to have slipped a bit.) Each die (known as "Orochi") will have up to four Bulldozer modules--in other words, eight integer cores and four floating point cores. Each module has a single 2MB level 2 cache (meaning the two integer
cores share that), and the overall chip of four modules shares an
additional level 3 cache of up to 8 MB. AMD also says it will have versions with six integer cores. This should allow AMD to market an 8-core version as having twice the number of physical integer cores as Intel's quad-core chips.

Intel, though, offers hyper-threading (its name for symmetric multi-threading) in which each core can handle two threads at once as a standard part of the Intel Core family based on Sandy Bridge. I expect AMD will point out that physical cores should be faster on multi-threaded applications if all other things are equal.

On the desktop side, the implementation is codenamed Zambezi and will be part of AMD's Scorpius platform. This chip, which will be sold under the FX brand name, is likely to go up against Intel's Core i7 line, which today includes quad-core Sandy Bridge versions (with integrated graphics) and very high-end six-core chips.

Today, Intel's six-core line is based on the older Nehalem architecture (coded named Gulftown and sold under the Extreme Edition label as the core i7-900 family). Intel hasn't formally announced it, but it's widely rumored to be releasing a chip known as Sandy Bridge-E ( E for Extreme) that is a six- or maybe even-eight core high-end desktop part, with the Sandy Bridge microarchitecture but without integrated graphics.

It will be particularly interesting to see how Zambezi performs versus Gulftown or a six-core Sandy Bridge-E, where you get AMD with 8 integer cores versus Intel with 6 physical cores but 12 threads. (Intel would seem to have an obvious advantage of floating point, with 6 cores versus four). But of course, it all depends on actual clock frequency and speed, which we don't know yet.

More likely, Zambezi will be priced and compared more against the quad-core chips than the Intel six-core. And that's where AMD should have an advantage, but again, it depends on the actual clock speeds and on the efficiency of the different architectures.

But AMD is hoping to make the largest gains in the server market, in part, because Intel has so thoroughly dominated the market in recent years. (I saw one market research report that says Intel currently has 96.5 percent of the server market.)

There AMD is planning a server version of the Orochi chips with the Bulldozer architecture, with a single-die version known as Valencia (to be called Opteron 4200 series) and a dual-die version called Interlagos (to be sold as the Operton 6200 series). This should lead to versions with 6 to 8 integer cores for mainstream servers and 12 to 16 integer cores for the higher-end servers. An Interlagos version should have a total of 16MB of Level 3 cache, with the dies connected by HyperTransport.

Intel recently starting shipping a high-end chip with up to 10 cores (and 20 threads), known as Westmere-EX and marketed under the Xeon E7 brand name. These are very high-end chips. The current top of the line E7-8870 has 10 cores and 20 threads with 30 MB of level 3 cache, runs at a nominal 2.4GHz with turbo mode up to 2.8GHz, and has a recommended price of $4,616.

Intel's current mainstream server line includes the Xeon E3 series, a single-socket version that's based on the Sandy Bridge architecture with 4 cores and 8 threads, with speeds up to 3.6GHz (and a turbo mode at 4GHz) at recommended prices ranging from $339 to $885.

But most interesting are the dual-socket versions known as Westmere-EP, based on the older architecture though still at 32nm, with up to 6 cores. These are likely to be replaced over time with a new server chip, known as Sandy Bridge-EP (and codenamed Jaketown, part of the Romley platform), which Intel described at the ISSCC conference earlier this year, and is supposed to ship by year's end. This will be based on the Sandy Bridge microarchitecture and has a ring bus for connecting up to 8 cores. Intel hasn't said, but it seems likely there will be a six-core variant as well, which will perhaps be similar to the rumored Sandy Bridge-E desktop chip.

Again, we don't yet know clock speeds and can't really judge the efficiencies of the architectures, but it looks like AMD will be putting out more physical integer cores (particularly in the Interlagos dual-die version), while Intel will have hyperthreading and likely more cache per core, as well as having a floating point core for each integer one and likely faster connections to external memory because of integrated PCI Express 3.0 support. If the clock speeds are equivalent, then the difference in performance should come down to the strengths of the actual architectures, the bandwidth of the connections and the caches, and the types of applications. It should be interesting to watch.

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